This youtube feature

There is a good configuration for learning English with youtube transcripts because Reading only, reading while listening, and listening only are these 3 methods for mastering any kind of language even a computer programming language. These methods work in tandem and there is a given balance that matches each learner's ability.

Then test in learning is not about measuring the learner or student but about improving the education or learning system. There isn’t a single application that consumes youtube videos and produces this measurable learning experience for people to learn and master the languages they want. I saw clearly the dropout effect of education in all youtube videos about learning. If online education imitates traditional education it is sure that it will be a failure because it will not leverage the power of the digital channel that allows personalization and measurements.